Excavator boom support



Dec. 21, 1954 .1. w. PAGE 2,697,527

EXCAVATOR BOOM SUPPORT Filed Jan. 21, 1950 2 Sheets-Sheet 1 Dec. 21, 1954 J w, PAGE 2,697,527

EXCAVATOR BOOM SUPPORT Filed Jan. 21, 1950 v 2 Sheets-Sheet 2 2,697,527 Patented Dec. 21, 1954 Application January 21, B59, Serial No.

a claims. (Cl. Zl2-59) This invention relates to an excavator boom support, and more particularly to means for maintaining the movable mast of a dragline excavator, and thus also the boom, in a desired position during working.

In excavating apparatus, particularly of the draglinc type, it has heretofore been common to support the relatively long boom, usually well over 100 feet in length, by pivotally mounting one end of the boom on the base portion of the excavator and connecting the outer end of the boom, as by cables, to the upper end of a relatively short movable mast pivotally mounted on the base near the boom mounting. The movable mast has been maintained in desired position during working by a second cable reeving or connection to a portion of the base structure, as a short fixed mast. Because of the normally rather small angle to the horizontal in which the boom Works the movable mast is a necessity to provide adequate support for the outer end of the boom without impossibly high stresses in the cables, and non maily the boom and movable mast are left connected in a given optimum relationship, with changes in boom angle necessary during working being effected by movement of the movable mast by the cable reeving between it and the fixed mast.

The cables effecting this movement or adiustment necessary at intervals during working are subject to substantial stress and have been a frequent point of failure, yet because of the need for making adjustments of the distance between the fixed and movable mast at interva s it has been considered impractical to rig a safety line, a: is usually done between the movable mast and boom, since a safety line between the fixed and movable menibers would have to be re-riggetl and changed in length on the occasion of each movement during working.

I have found that i can overcome these and other difliculties and provide a very much safer, stronger, and more desirable supporting arrangement in such an excavator. Broadly stated, l rig the movable mast and boom together with cable reeving and a safety line in the conventional way, and then in addition to the cable reeving between the fixed and movable mast, l provioe a rigid inter-connecting member adjustably but fixedly connectable between the masts to maintain them in desired relationship during working, with the reeving then providing a safety line; and I provide support means for the inter-connecting member enabling convenient disconnection of one end and movement between various fixed positions while ing the parts substantially in operating or working relationship.

One feature of this invention is that it provides an improved supporting arrangement for the boom of an excavator, particularly of the dragline type; another feature of this invention is that it provides an improved adjustable connection, with safety features, between the movable mast and a portion of the main base structure, as a fixed mast; another feature is the provision of a supporting arrangement which enables convenient variation in position of the mast at frequent intervals during working, yet which provides a very rigid and satisfactory support during working, with a much higher degree of safety than has heretofore been possible; and yet another feature of this invention is the provision of means for supporting the ri id inter-connecting member in substantially working relation to the movable mast during movement thereof, as by the cable reeving, to change the position of the mast and boom. Other features and advantages will be apparent from the following specification and the drawings, in which:

Figure l is a side elevational view of a dragline excavator embodying my invention; Figure 2 is a fragmentary enlarged side elevation of the portion of the excavator with which I am here particularly concerned; Figure 3 is a transverse sectional view along the line 33 of Figure 2; and Figure 4 is a detailed sectional view along the line l-d of Figure 2.

in the particular embodiment of my invention illustrated 11] the drawings, which will be understood to be only one of many forms in which the invention may be embodied, the excavator is shown as having a main base structure indicated in general as 10 and consisting as its principal parts of a base proper here indicated as 11, a housin or shin structure 12 having a relatively short fixed mast rising therefrom (sometimes termed the m-flilfl'ifi in the field), and propelling mechanism here shown as le s l4 and feet 15 on each side. This main portion of tne excavator, here being termed broadly the main base structure, may be of any suitable size and shape and capable of being moved from one excavating position to another in any desired manner, walking mechisms being the subiect of other issued patents to which rercrence may be made, as for example, my Patent 2,290,118 of July 14, 1942.

Mounted pivotally at the forward end of the main base structure is the boom here identified as 16, and pivot-ally mounted about an axis near but not exactly coaxial with the boom is a movable mast 17. The outer end of the boom is connected to the upper end of the mast in a manner well known in the field, as by adjustable cable reeving 13. Since this need seldom be changed, safety line 19 is preferably also rigged; and additional support for intermediate portions of the boom may be provided by the lines 29 and 21 as in a manner more it escribed in my Patent 2,255,568 of September A n t line 22 extends from suitable operating means in the main base structure, as a cable drum and drive motor arrangement therefor out over a sheave at the end of the boom; and a load line 23 extends from imilar suitable controlling means in the main base strucure, as a motor driven drum. The hoist and load lines used to operate the actual excavating element, as a agline bucket. Such a bucket well known in the rt and will not be further described here as, if desired, reference may be had to my Reissue Patent 21,664 is-- sued December l7, 1940, for a full illustration and description of the operation of a bucket of the type I prefer. known generally in the trade as a Page Automatic bucket. Means must be provided for supporting the movable mast, and imalso the boom, in working position, and it is this supporting arrangement with which I am particularly concerned. Not only must this supporting arrangement be of considerable strength to handle the tresses imposed during operation of large buckets at the ads of booms well over lOO-feet long, but it must also rovide for relatively quick and convenient adjustment variation of the working position of the movable mast and boom so that appropriate changes in this position may be at relatively frequent intervals during working. Referring now more particularly to the fragmen- 2, this supporting ta y enlarged view comprising Figure arrangement will be described.

The top member or upper end of the A-frame, or relatively short fixed mast, is provided with appropriate cable reeving here shown as comprising the sheaves 25a and 25b, the cable 25 and the sheaves 27a and 2712 connected to the upper end of the movable mast 17. The end 260 of the cable extends into a suitably driven drum in the main base structure and provides means for varying the position or" the movable mast (and thus also of the boom) conveniently whenever the rigid inter-connecting arrangement hereinafter described is temporarily disconnected.

The rigid interconnecting member serving to adjustably but fixedly connect the upper ends of the fixed and movable masts during working is here identified as 23. This member 23 is pivotally connected to the upper end of the movable mast 17 at the point 29 and has its other end adapted to be connected to the fixed mast at any selected one of a plurality of trated as the four points 30a-d. It will be understood that any suitable number of such fixed connecting points may be used, the four shown being representative only.

Referring to Figures 2 and 4 it will be seen that the upper end of the fixed mast comprises a pair of spaced plates 13a and 13b, and that the end of the rigid interconnecting member 28 cooperating with these plates is T-shaped, with the web portion adapted to be received in sliding engagement between the plates 13a and 13b. The plates are provided with a pair of opposite holes adapted to register with any selected one of the holes 30a-d, as the effective length of the rigid inter-connection is varied by operation of the cable reeving, and when a selected one of the points has been reached, the rigid inter-connecting member 28 is locked to the top of the short fixed mast by inserting a clevis pin through the registering openings at the selected point, as at the point 30b as illustrated. This pin is here identified as 32, and can be readily removably held in position by any suitable means, as by a cotter pin, after it has been inserted.

After the movable mast 17 has been moved to a desired new position (the holding pin having been removed during this period) it is locked in such position by replacement of the pin and the cable reeving is then very slightly eased off and the drum locked in position. While it is almost impossible for the rigid inter-connecting support arrangement which I have provided to fail during working, nevertheless the cable reeving provides a safety line acting automatically if such an event should ever occur. Moreover, it does so without the necessity of any independent rigging or changing of safety lines and in an automatic manner, which an operator does not neglect to do. The result is a very stable and steady supportfixed points, here illusing arrangement for the movable mast which permits quick and easy changing to facilitate mast and boom position variations, yet which provides the utmostsafety during working.

In order to facilitate return of the rigid interconnecting member to operating relationship with the top on the fixed mast whenever the movable mast and boom have been lowered well below normal operating positions, as for oiling of the sheaves, checking of the rigging, or the like, I provide a supporting arrangement for the interconnecting member which supports it in substantially angular operative relationship to the movable mast. While this may take various forms, it is here illustrated as a supporting member 33 which is rigidly attached to the movable mast 17 at an angle substantially perpendicular to the interconnecting member 28, as by being welded to plates 35; pin 36 is used to hold the parts together before and during welding and may be left in place after welding to strengthen the connection. The upper end of the supporting member is here shown as providing a forked portion comprising the arms 33a and 33b receiving the inter-connecting member 28 therebetween (see Figure 3). The relationship of the parts is preferably such that the inter-connecting member 28 is out of engagement with the bottom of the supporting fork when connected as shown in Figure 2, the fork arms preferably being long enough to permit the inter-connecting member 28 to slide up or down slightly, without coming out from between the arms during the slight angular changes relative to the mast resulting from selection of different ones of the connecting hand, if the movable mast and boom are lowered so that the inter-connecting member 28 entirely leaves its normal position between the plates 13a and 13b, it is supported by engagement with the bottom of the fork porpoints. On the other tion of the supporting member 33; and when the mast and boom are again pulled up, the member 28 returns automatically and easily to working position between the plates 13a and 13b just mentioned. This return is facilitated by providing an upwardly turned end portion 28a which automatically takes the load off the supporting member as the inter-connecting member 28 re-enters the top of the fixed mast and boom supported thereby.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

I claim:

1. In a dragline excavator having a movably mounted boom, a supporting arrangement therefor comprising: a movable mast; means connecting the movable mast and the boom for rendering them normally movable together; a fixed mast; cable reeving for varying the relationship between the movable and fixed masts; a rigid interconnecting member pivotally connected at one end to the upper end of the movable mast and adjustably but fixedly connectable to the fixed mast to connect the masts in desired relationship during working; and means for supporting the interconnecting member substantially in working relation to the movable mast during operation of the cable reeving.

2. In a dragline excavator having a movably mounted boom, 21 supporting arrangement therefor comprising: a movable mast; means connecting the movable mast and the boom for rendering them normally movable together; a fixed mast; cable reeving for varying the relationship between the movable and fixed masts; a rigid interconnecting member pivotally connected at one end to the upper end of the movable mast and connectable at any selected one of a plurality of fixed points to the fixed mast to connect the masts in desired relationship during working; and means for supporting the interconnecting member substantially in working relation to the movable mast during operation of the cable reeving.

3. In excavating apparatus having a main base structure: a boom movably mounted on said base structure; a mast movably mounted on said base; means connecting said mast and boom; means for moving said movable mast; a rigid interconnecting member pivotally connected at one end to the upper end of the movable mast and connectable to a portion of the main base structure at any selected one of a plurality of fixed points during working; and a supporting member extending between the mast and interconnecting member for maintaining them substantially in working relationship during movement of the mast.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 739,955 De Vow Sept. 29, 1903 1,187,699 Bathrick June 20, 1916 1,195,461 Greene Aug. 22, 1916 1,434,076 Watkins Oct. 31, 1922 1,874,189 Howard Aug. 30, 1932 2,186,372 Elgh Jan. 9, 1940 2,374,074 Berby et al. Apr. 17, 1945 2,391,440 Anderson Dec. 25, 1945 2,515,777 King et al July 18, 1950 2,558,686 Hubbard June 26, 1951 

